a(n) = Sum_{k=1..n} F(n mod k) where F = A000045, the Fibonacci numbers.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =3a(5) =2a(6) =6a(7) =5a(8) =9a(9) =9a(10) =17a(11) =13a(12) =26a(13) =26a(14) =39a(15) =39a(16) =66a(17) =61a(18) =104a(19) =102a(20) =156a(21) =162a(22) =265a(23) =249a(24) =405a(25) =419a(26) =646a(27) =652a(28) =1059a(29) =1031